Simply remove the floor plate on your magazine, and slide this special extension from Pearce on in its place, and increase your magazine capacity by two rounds. It works especially nicely on the Subcompact models, as it adds 1" of length to the grip and provides a larger grip for an easy draw and more controlled shooting. The extension is designed to blend perfectly with the new Springfield XD Mod.2 grip design. It works with both 9mm and .40 S&W magazines, but will not fit .45 ACP magazines.